This application claims the priority of Japanese Patent Application No. 2-128258 filed May 17, 1990 which is incorporated herein by reference.
1. Field of the Invention
This invention relates to a block copolymer, a process for preparing the same and the use thereof. More particularly it relates to a block copolymer containing an unsaturated group sensitive to activation energy rays such as ultraviolet rays and electron beams and also fluorine atoms having water and oil repellent properties.
2. Description of the Related Art
It is known that a fluorine containing block copolymer is useful as a surface modifier for polymeric materials. It is disclosed, for example, in Japanese Unexamined Patent Publication (Kokai) No. 60-22410 that when a perfluoroalkyl containing block copolymer is added to a polymeric material, the block copolymer is oriented on the surface of the polymeric material to impart water and oil repellency and antifouling properties to the surface of the material. Japanese Unexamined Patent Publication (Kokai) No. 2-4877 also discloses coating the surface of synthetic resin sheets with a fluorine containing block copolymer. When such sheets are stacked, they do not stick together and thus facilitate peeling of each sheet. Further, Japanese Unexamined Patent Publication (Kokai) No. 2-4812 discloses that addition of a fluorine containing block copolymer to an electrical insulating material can impart moisture resistance to the material.
On the other hand, some fluorine containing polymers are known which can accelerate curing by irradiation of an activation energy ray. Such polymers are used as solder resist materials and coating materials. For example, Japanese Unexamined Patent Publication (Kokai) No. 58- 215411 discloses that a radical copolymerization reaction between a monomer having photo-dimerization reactivity and a fluorine containing monomer affords a photosensitive fluorine containing polymer. It is also disclosed in Japanese Unexamined Patent Publication (Kokai) Nos. 62- 25104 and 63-301268 that a fluorine containing polymer is produced through copolymerization between a hydroxyl containing vinyl ether and a fluoroolefin, followed by reaction of the resulting fluorine containing copolymer with a compound having an isocyanate group and an unsaturated group to afford a polymer curable by an activation energy ray. In addition, Japanese Unexamined Patent Publication (Kokai) No. 62-190264 discloses that reaction between three kinds of compounds, i.e. a fluorine containing block copolymer having a hydroxyl group, an isocyanate compound and a compound having a hydroxyl group and an unsaturated group forms a photosensitive polymer.
However, since the block copolymer containing an unsaturated group and fluorine atoms described in the above publications is produced by use of a compound having an isocyanate group and an unsaturated group, it suffers a problem that gelation is liable to occur during the reaction. It is possible to use the isocyanate compound in a large amount for preventing the gelation, but polymerization of the fluorine containing block copolymer proceeds to increase the molecular weight thereof, while the proportion of the fluorine containing polymer moiety is reduced. Thus, when the above block copolymer is used as a surface modifier, it tends to show reduced surface activating power, failing to impart sufficient water and oil repellent properties derived from fluorine atoms to the surface of the polymer. In addition, the polymer has low surface orientation in the fluorine containing polymer moiety and the network macromolecularization proceeds in the portion that is not irradiated with activation energy rays. Therefore, when the polymer is used as a resist material, it suffers a problem that it can not always exhibit the functions of the fluorine containing polymer and it lacks the desired reactivity with various developing agents.